Amyloidosis

Amyloidosis (am-uh-loi-DO-sis) is a rare disease that occurs when a substance called amyloid builds up in your organs. Amyloid is an abnormal protein that is usually produced in your bone marrow and can be deposited in any tissue or organ.

Amyloidosis can affect different organs in different people, and there are different types of amyloid. Amyloidosis frequently affects the heart, kidneys, liver, spleen, nervous system and digestive tract. Severe amyloidosis can lead to life-threatening organ failure.

There's no cure for amyloidosis. But treatments can help you manage your symptoms and limit the production of amyloid protein.

When to see a doctor

Purpura around the eyes

Enlarged tongue

In general, amyloidosis is caused by the buildup of an abnormal protein called amyloid. Amyloid is produced in your bone marrow and can be deposited in any tissue or organ. The specific cause of your condition depends on the type of amyloidosis you have.

There are several types of amyloidosis, including:

Immunoglobulin light chain (AL) amyloidosis, the most common type, can affect your heart, kidneys, skin, nerves and liver. It was previously known as primary amyloidosis. It occurs when your bone marrow produces abnormal antibodies that can't be broken down. The antibodies are deposited in your tissues as amyloid, interfering with normal function.

AA amyloidosis mostly affects your kidneys but occasionally your digestive tract, liver or heart. It was previously known as secondary amyloidosis. It occurs along with chronic infectious or inflammatory diseases, such as rheumatoid arthritis or inflammatory bowel disease.

Hereditary (familial) amyloidosis is an inherited disorder that often affects the liver, nerves, heart and kidneys. One type is caused by a certain amyloid (transthyretin amyloid) that can affect the nervous system or the heart. African-Americans have a greater risk of this type than do Caucasians. It is thought to be a significant cause of heart failure in African-American men.

Dialysis-related amyloidosis develops when proteins in blood are deposited in joints and tendons — causing pain, stiffness and fluid in the joints, as well as carpal tunnel syndrome. This type generally affects people on long-term dialysis.

Age. Most people diagnosed with AL amyloidosis, the most common type, are age 50 or older, although earlier onset occurs.

Gender. Nearly 70 percent of people with AL amyloidosis are men.

Other diseases. Having a chronic infectious or inflammatory disease increases your risk of AA amyloidosis.

Family history. Some types of amyloidosis are hereditary.

Kidney dialysis. Dialysis can't always remove large proteins from the blood. If you're on dialysis, abnormal proteins can build up in your blood and eventually be deposited in tissue. This condition is less common with modern dialysis techniques.

The potential complications of amyloidosis depend on which organs the amyloid deposits affect. Amyloidosis can seriously damage your:

Kidneys. Amyloid can harm the kidneys' filtering system, causing protein to leak from your blood into your urine. The kidneys' ability to remove waste products from your body is lowered, which may eventually lead to kidney failure.

Heart. Amyloid reduces your heart's ability to fill with blood between heartbeats. Less blood is pumped with each beat, and you may experience shortness of breath. If amyloidosis affects your heart's electrical system, your heart rhythm may be disturbed.

Nervous system. You may experience pain, numbness or tingling of the fingers or numbness, lack of feeling or a burning sensation in your toes or the soles of your feet. If amyloid affects the nerves that control your bowel function, you may experience periods of alternating constipation and diarrhea. Sometimes amyloidosis affects nerves that control blood pressure, and you may experience dizziness or near fainting when standing too quickly, as a result of a drop in your blood pressure.

Amyloidosis is often overlooked because the signs and symptoms can mimic those of more-common diseases. Diagnosis as early as possible can help prevent further organ damage. Precise diagnosis is important because treatment varies greatly, depending on your specific condition.

Your doctor is likely to start with a thorough medical history and physical exam. After that, you may have:

Laboratory tests. Your blood and urine may be analyzed for abnormal protein that can indicate amyloidosis. Depending on your signs and symptoms, you may also have thyroid and liver function tests.

Biopsy. A tissue sample may be taken and checked for signs of amyloidosis. The biopsy may be taken from your abdominal fat, bone marrow, or an organ such as your liver or kidney. Tissue analysis can help determine the type of amyloid deposit.

Imaging tests. Images of the organs affected by amyloidosis can help establish the extent of your disease. Echocardiogram may be used to assess the size and functioning of your heart. Other imaging tests can evaluate the extent of amyloidosis in your liver or spleen.

There's no cure for amyloidosis. But treatment can help manage signs and symptoms and limit further production of amyloid protein. Specific treatments depend on the type of amyloidosis.

For AL amyloidosis, treatment options include:

Chemotherapy, to stop the growth of abnormal cells that produce amyloid.

Peripheral blood stem cell transplant, in which your own stem cells are collected from your blood and stored for a short time while you have high-dose chemotherapy. The stem cells are then returned to your body via a vein. This treatment is most appropriate for people whose disease isn't advanced and whose heart isn't greatly affected.

Treatment for other types of amyloidosis

AA amyloidosis. The underlying condition is treated with medication — for example, an anti-inflammatory medication to treat rheumatoid arthritis.

Hereditary amyloidosis. Liver transplantation may be an option because the protein that causes this form of amyloidosis is made in the liver.

Dialysis-related amyloidosis. Options include changing your mode of dialysis or having a kidney transplant.

Medications

To manage ongoing signs and symptoms of amyloidosis, your doctor also may recommend:

Pace yourself. If you feel short of breath, take a break. You'll need to avoid strenuous activities, but you may be able to continue normal daily activities, such as going to work. Talk to your doctor about an appropriate level of activity for you.

Follow a balanced diet. Good nutrition is important to provide your body with adequate energy. Follow a low-salt diet if your doctor recommends it.